Multi-layer impact resistant bumper

ABSTRACT

An impact resistant bumper device that is elongated along a longitudinal axis and mountable on a mounting member, the device having a cross-section having an open undersurface configuration comprising:
         a first layer of a first polymer material;   a second layer of a second polymer material;   a third layer of a third polymer material;   wherein the first polymer material has been melted at least once prior to the extrusion cycle, the second polymer material is first melted during the extrusion cycle and the third polymer material is first melted during the extrusion cycle.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/236,107 filed Sep. 23, 2008, which is a continuation of U.S. patentapplication Ser. No. 10/954,432, filed Sep. 30, 2004, which claims thebenefit of priority under 35 U.S.C. Sections 119 and/or 120 to theextent applicable to U.S. Provisional patent application Ser. No.60/508,102 filed Oct. 2, 2003 for Multi-Layer Impact Resistant Bumper.

FIELD OF THE INVENTION

The present invention relates to multilayered products comprised ofpolymeric material and methods for producing such products. Moreparticularly the invention relates to extruded or molded polymericmaterial products comprising layers that are bonded to each other, eachlayer comprising a polymeric material having a different selecteddurometer, hardness, bendability, impact resistance and/or melting pointand/or concentration of dye and/or plasticizer materials.

BACKGROUND OF THE INVENTION

Extruded or injection molded products comprising two or more layers ofpolymer material are typically produced using complex molding orextrusion equipment and/or requiring complex processing steps that aredifficult to reproduce from one extrusion or molding cycle to the nextcycle. Processing methods for producing products comprised of polymermaterials are typically developed by trial and error experimentationwith a variety of different polymer materials having specific propertiesand molecular weights which, once determined are specific to productionof the desired product and cannot be varied without substantiallychanging the end product.

SUMMARY OF THE INVENTION

The present invention relates to structural products that comprise abody of two or more polymer materials adhered or bonded to each othereach polymer material having a different durometer, hardness,bendability, molecular weight or melting point or concentration of dyematerials and/or plasticizers. The structural products of the inventionare preferably formed as a multi-layered strip of polymer materialswhich is/are resistant to impact by solid objects and/or shock absorbentand resistant to shrinkage along the longitudinal or axialdirection/length of the strip-form product.

In accordance with the invention there is provided an elongated strip ofpolymer material having a cross-section comprising:

a first inner core layer of a first polymer material having a selectedconfiguration along the cross-section of the strip;

a second outer layer of a second polymer material bonded to an outersurface of the first inner core layer having a second selectedconfiguration along the cross-section;

wherein the first polymer material has a softness, hardness or durometerselected to be manually bendable and compressible; and,

wherein the second polymer material has a durometer or hardness greaterthan the durometer or hardness of the first polymer material.

The first and second layers are preferably co-extruded simultaneouslythrough a die and bonded during their simultaneous co-extrusion. Thesecond polymer material comprises a meltable polymer material that ismelted for the first time after its initial manufacture during theco-extrusion. The first polymer material comprises a meltable polymermaterial that has been melted at least one once prior to theco-extrusion. The second polymer material typically contains at leastone selected dye. The first polymer material typically contains at leasttwo selected dyes.

The elongated strip may further comprise a third layer of a polymericmaterial bonded to an inner surface of the first layer. In such anembodiment, the first, second and third layers are co-extrudedsimultaneously through a die and bonded during their simultaneousco-extrusion. The third layer typically comprises a polymeric materialthat is first melted during the co-extrusion.

Further in accordance with the invention there is provided, an elongatedstrip of polymer material extruded in an extrusion cycle having across-section comprising:

a first inner core layer of a first polymer material having a selectedconfiguration along the cross-section of the strip;

a second outer layer of a second polymer material bonded to an outersurface of the first inner core layer having a second selectedconfiguration along the cross-section;

wherein the second polymer material is first melted during the extrusioncycle; and

wherein the first polymer material has been melted at least once priorto the extrusion cycle.

In another aspect of the invention there is provided, a method ofproducing a structural body of two or more layers of polymeric material,the method comprising:

selecting a first polymer material that has been melted and cooled tosolid form;

selecting a second polymer material that has not been melted;

extruding the first and second polymer materials simultaneously inmolten form through a selected mold or die in first and second strips;

layering the simultaneously extruded first and second strips intocontact with each other in their molten form upon exiting the selectedmold or die in a configuration wherein the first strip as formed has anouter surface and the second strip is deposited on the outer surface ofthe first strip.

The step of selecting the first polymer material includes selecting apolymer material that contains a dye material and has been melted priorto the step of extruding and most preferably comprises selecting amixture of two or more polymer materials that have been melted andcooled to solid form.

The step of extruding typically comprises forming the first polymericmaterial upon exiting the mold or die into a strip form having an outervisible surface and an undersurface wherein, the step of layeringcomprises layering the second extruded polymer onto the outer visiblesurface of the second polymer material.

The step of selecting the second polymer material typically comprisesselecting a predetermined first polymer material having a firstdurometer, hardness, bendability or molecular weight wherein thepredetermined polymer material converts upon melting and cooling to aconverted state having a second durometer, hardness, bendablity ormolecular weight that is less than the first durometer, hardness,bendability or molecular weight; and wherein the step of selecting thefirst polymer material comprises selecting the predetermined polymermaterial in the converted state.

The step of selecting the second polymer material may comprise selectinga predetermined second polymer material and the step of selecting thefirst polymer material may comprise selecting a mixture of two or morepolymer materials each being comprised of the predetermined secondpolymer material and each containing a dye. In another aspect of theinvention there is provided, a method of producing a structural body oftwo or more layers of polymeric material, the method comprising:selecting a first polymer material that has been melted and cooled tosolid form;

selecting a second polymer material that has not been melted;

extruding the first and second polymer materials simultaneously inmolten form through a selected mold or die into first, second and thirdstrips;

layering the simultaneously extruded first, second and third strips intocontact with each other in their molten form upon exiting the selectedmold or die;

wherein the first strip is comprised of the first polymer material andthe second and third strips are comprised of the second polymermaterial; and;

wherein the first strip is sandwiched between the second strip and thethird strip.

In such an embodiment, the step of selecting the second polymer materialmay comprise selecting a predetermined polymer material having a firstdurometer, hardness, bendability or molecular weight wherein thepredetermined polymer material converts upon melting and cooling to aconverted state having a second durometer, hardness, bendablity ormolecular weight that is less than the first durometer, hardness,bendability or molecular weight; and wherein the step of selecting thefirst polymer material may comprise selecting the predetermined polymermaterial in the converted state.

The step of selecting the second polymer material may comprise selectinga predetermined second polymer material wherein the step of selectingthe first polymer material may comprise selecting a mixture of two ormore polymer materials each being comprised of the predetermined secondpolymer material and each containing a dye.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an underside/perspective cross sectional view of a compositematerial extruded bumper product according to the invention showing asolid strip form extruded body of material comprising a top outer layerof relatively hard polymer material, an inner or intermediate layer ofrelatively soft or less hard and more bendable polymer material and anundersurface strip of relatively hard, shrink resistant polymermaterial;

FIG. 2 is a topside/perspective cross sectional view of the Fig. productshowing the product mounted or snap fit onto a railing;

FIG. 3 is a schematic cross sectional view of the FIG. 1 product;

FIG. 4 is a rear elevational view of the first plate as seen along line4-4 of FIG. 3;

FIG. 5 is a rear elevational view of the second plate as seen along line5-5 of FIG. 3;

FIG. 6 is a rear elevational view of the third plate as seen along line6-6 of FIG. 3;

FIG. 7 is a rear elevational view of the fourth plate as seen along line7-7 of FIG. 3;

FIG. 8 is a front elevational view of the fourth plate as seen alongline 8-8 of FIG. 3;

FIG. 9 is a front cross-sectional view of the FIG. 1 product; and,

FIG. 10 is an exploded perspective view of the third and fourth platesshown in FIG. 3.

DETAILED DESCRIPTION

FIGS. 1, 2 and 9 show an extruded length of a multi-strip formed bumperproduct 8 comprising an outer facing strip 10 of relatively hard polymermaterial, and intermediate strip 20 of relatively soft, rubbery orbendable polymer material and an undersurface strip 40 of relativelyhard, rigid, shrink resistant polymer material. The outer coat or stripcomponent/layer 10 is bonded during the extrusion process, preferablyimmediately upon exit from the final extrusion die, to the outer surfaceof the inner soft or manually bendable layer or strip 20 such that theend product assumes the outward visual appearance of a relatively hard,shiny surface as opposed to the inner layer 20 which cannot be visuallyseen when mounted on a rail 30 as shown in FIG. 2.

FIG. 2 shows the elongated strip-like product 8 mounted on a rigid,inflexible metal rail 30 by snap fitting of preformed tongues or detents55 formed on the underside 57, FIG. 1, of the core 20 strip/layer onto acomplementary receiving set of grooves or detents 59 formed on theoutside surface the rail 30 shown in FIG. 2.

As shown in FIG. 3, the composite material feed for the core 20 is feddirectly from the exit barrel 6 of the extruder through a centralcomposite material bore 50 that extends through each of plates 1-4. Thepolymer feed for the cap coat 10 is fed through an aperture 60 extendingfrom the exit side to the entrance side of plate 4 through plate 4, thefeed then being routed through a bore 70, FIGS. 7, 8, 10 on the entranceside of plate 4 such that the cap coat material feed is ultimatelyrouted through plate 4 and out the exit side of bore 70 on the exit sideof plate 4, FIGS. 7, 8, 10 simultaneously with the extrusion of the feedmaterial for the core 20 being routed through central bore 50. Thepolymer feed for the rigid non-shrink strip 40 is initially fed throughan aperture 80 extending from the exit side to the entrance side ofplate 4 through plate 4, the feed then being routed through a groove 90,FIGS. 7, 8, on the entrance side of plate 4 such that the rigid strip 40material is ultimately routed through plate 4 and out the exit side ofbore 100 on the exit side of plate 4 simultaneously with the extrusionof the feed material for the core 20 being routed through central bore50 and the feed material for the cap coat 10 being routed through bore70. Thus all three separate streams of polymer materials comprising thecap coat 10, core 20 and rigid undersurface strip 40 are simultaneouslyco-extruded and come into contact with each other in a molten stateimmediately upon exit from the exit side of plate 4. Once the threeco-extruded streams of materials come into contact with each other inthe molten state, the materials firmly bond to each other during andupon cooling to form the product shown in FIGS. 1, 2, 9.

FIG. 3 shows an additional end plate 5 that may be used together withthe plates 1-4 assembly, the exact configuration and use of plates andequipment to effect the fluid material feed connections to the bores ofplates 1-4 being a matter of design choice for the skilled artisan. Thedisclosed embodiment showing the use of four separate plates 1-4 isshown for purposes of example only. Any number or configuration ofextrusion plates that achieve the function of routing of thethermoplastic polymer materials as shown may be used in the process.Positioning the exit ends of feed bores 50, 70, 80 in close adjacency toeach other such that the separate streams of exiting polymer materialscontact the surfaces of each other upon exit from the extrusion platesis most preferred so that the separate streams of exiting polymermaterials come into contact with each other in a molten stateimmediately upon exit and thereby adhere to each other upon cooling fromthe molten state to a stable cooled state. When the separate streams ofpolymer materials come into contact with each other in the molten statethe mating surfaces mix together somewhat at the point of contact andupon cooling to a crystalline state become essentially adhered to eachother to form a the unitary product 8 shown in FIGS. 1, 2, 9. Theseparate streams of extruded polymer materials may alternatively bebonded to each other with a bonding material.

FIGS. 3, 10 show a solid rod or wire 200 that may be positioned throughthe end portion of bore 50 in the middle of the detent 55 configurationof the core 20 strip to enable an elongated aperture 25 to be formedwithin the body of the detent during the extrusion process to impartadditional bendability or flexibility to the detent 55. Such additionalflexibility imparted to the detent 55 better enables the detent to bemanually snap fit around or over the outer surface of the complementaryprotrusion or detent 59 of the rail 30 onto which the bumper strip 8 ismounted. The snap fitted mounting of detents 55 onto the protrusions 59firmly holds the bumper 8 on the rail 30.

The core material 20 typically comprises a mixture of polymer materialsthat have been previously processed and melted in a prior extrusion orinjection molding cycle, e.g. a mixture of scrap materials from previousextrusion cycle runs of one or more selected thermoplastic polymermaterials such as polyvinyl chloride (PVC) where each scrap materialcontains a different concentration/amount of dye material and/or adifferent durometer or hardness. The subsequent extrusion processingcycle carried out on previously extruded or molded materials causes thecomposite material now being melted a second time in the course of anextrusion or molding process to assume a lower durometer than theoriginally extruded product comprising virgin material and/or a greaterrubberiness, flexibility or bendability than the original virginmaterial. The lower durometer of scrap material may also be a result ofthe scrap materials containing several different dye and other additivessuch as plasticizers and the like.

As used herein the phrase “melted for the first time” or “first melted”or the like means that the polymer material has not been previouslymelted during an extrusion or molding process, it being understood thatthe starting polymer material may have been previously in a molten formas a result of its having been produced/manufactured in the firstinstance.

The cap coat 10 thermoplastic material selected is preferably virginpolymer material that has not been previously extruded or otherwisemelted and typically does not initially contain a dye. The cap coat 10material upon extrusion has a higher durometer, rigidity and lessrubberiness, flexibility and bendability than the core material 20. Oneor more dye materials that comprise between about 3% and about 10%, e.g.4-7%, by weight of the cap coat polymer material may be mixed with/addedto the thermoplastic starting feed material for the cap coat 10.

The non-shrink strip material 40 is also preferably comprised of avirgin polymer material that has not been previously extruded orotherwise melted. Most preferably, the non-shrink strip material is themost rigid of the three polymer materials and is the most resistant toshrinkage particularly in/along the longitudinal direction of theelongated strip-form product 8. The non-shrink material may comprise thesame or substantially the same virgin polymer material as the core 20material. The rigid strip 40 provides a particular resistance toshrinkage of the core material 20 along the longitudinal or axial lengthof the elongated extruded strip-like product 8 by virtue of being bondedto the underside of the core 20 strip. Such resistance to shrinkage byvirtue of the bonding of the non-shrink strip 40 to the core stripcomponent 20 thus obviates the necessity for replacing edge, end orcorner pieces that are typically attached to or mounted at the ends of afinished strip product 8 once installed on a rail 30 in an actual shelf,counter or other retail store environment.

The polymer material selected for use in comprising the cap coat 10 andthe core 20 typically comprises the similar basic polymers, mixture ofpolymers or thermoplastic materials, e.g. thermoplastic polyvinylchlorides, nylons, polyesters, polyethers, polyamides, rubbers and latexrubber materials and copolymers of one or more of all of the foregoing.That is the polymer materials of which the cap coat 10 and the core 20are comprised typically have essentially the same units making up thepolymer backbone. The polymer material of the cap coat 10 and core 20materials typically differ somewhat in polymer chain length, degree ofcross polymerization (if any) or in concentration and composition of dyematerials contained within the matrix of the materials. For example, thevirgin cap coat 10 material typically comprises a polymer materialhaving a durometer of between about 75 and 90, e.g. 80-85, and the corelayer 20 material comprises a mixture of two or more scrap materialsthat were originally extruded from the same basic material as the capcoat 10 material containing the same or different dye materials at thesame or different concentrations as the cap coat 10 material contains.

Polymer materials suitable for use in the invention are thermoplasticpolymers that are relatively pliable or manually bendable such aspolyvinyl chloride, polyamide, polyether, polyester and copolymers ofall of the foregoing with one or more of each other or with urethane orother polymer units that impart a suitable manual bendability to the endpolymer. Stiffeners, plasticizers, catalysts and the like may becontained within the polymer materials to impart any desired degree offlexural modulus, hardness, impact resistance and likemechanical/physical properties to the polymer material.

1. An impact resistant bumper device that is elongated along alongitudinal axis and mountable on a mounting member, the device havinga cross-section having an open undersurface configuration comprising: afirst layer of a first polymer material having a first hardness ordurometer; a second layer of a second polymer material having a secondhardness or durometer; wherein the first layer is formed into an innercore body having an outer surface and an open undersurface; wherein thesecond layer is formed into a layer bonded to the outer surface of thefirst layer; a third layer of a third polymer material formed into anelongated strip bonded to the undersurface of the first layer; whereinthe first polymer material has been melted at least once prior to theextrusion cycle, wherein the second polymer material is first meltedduring the extrusion cycle; and, wherein the third polymer material isfirst melted during the extrusion cycle.
 2. The elongated strip of claim1 wherein the first and second layers are co-extruded simultaneouslythrough a die and bonded during the extrusion cycle.
 3. The elongatedstrip of claim 1 wherein the first polymer material has a hardness ordurometer selected to be manually bendable and compressible; and,wherein the second polymer material has a hardness or durometer greaterthan the hardness or durometer of the first polymer material.
 4. Theelongated strip of claim 3 wherein the third polymer material has ahardness or durometer greater than the hardness or durometer of thefirst polymer material.